U.S. patent application number 14/769843 was filed with the patent office on 2016-01-21 for mid-turbine frame rod and turbine case flange.
The applicant listed for this patent is UNITED TECHNOLOGIES CORPORATION. Invention is credited to Keshava B. Kumar.
Application Number | 20160017754 14/769843 |
Document ID | / |
Family ID | 51491769 |
Filed Date | 2016-01-21 |
United States Patent
Application |
20160017754 |
Kind Code |
A1 |
Kumar; Keshava B. |
January 21, 2016 |
MID-TURBINE FRAME ROD AND TURBINE CASE FLANGE
Abstract
A turbine section of a gas turbine engine includes a first
turbine supported for rotation about an axis, a second turbine
spaced axially aft of the for first turbine section for rotation
about the axis, and a mid-turbine frame disposed between the first
turbine and the second turbine defining a passage between the first
turbine and the second turbine. A first case surrounds the first
turbine and a second case surrounding the second turbine and
attached to the first case. The mid-turbine frame is disposed
between the first turbine section and the second turbine section
and includes at least one support structure extending through an
interface between the first turbine case and the second turbine
case.
Inventors: |
Kumar; Keshava B.; (South
Windsor, CT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
UNITED TECHNOLOGIES CORPORATION |
Hartford |
CT |
US |
|
|
Family ID: |
51491769 |
Appl. No.: |
14/769843 |
Filed: |
February 18, 2014 |
PCT Filed: |
February 18, 2014 |
PCT NO: |
PCT/US2014/016754 |
371 Date: |
August 24, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61772702 |
Mar 5, 2013 |
|
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|
Current U.S.
Class: |
60/805 ;
415/213.1 |
Current CPC
Class: |
F02C 3/04 20130101; F01D
25/162 20130101; F01D 25/243 20130101; F05D 2220/323 20130101; F02C
7/20 20130101; F02K 3/06 20130101 |
International
Class: |
F01D 25/24 20060101
F01D025/24; F02C 3/04 20060101 F02C003/04; F02K 3/06 20060101
F02K003/06; F02C 7/20 20060101 F02C007/20 |
Claims
1. A gas turbine engine comprising: a fan including a plurality of
fan blades rotatable about an axis; a compressor section; a
combustor in fluid communication with the compressor section; a
turbine section in fluid communication with the combustor, wherein
the turbine section includes a first turbine section disposed
within a first case and a second turbine section disposed within a
second case; and a mid-turbine frame disposed between the first
turbine section and the second turbine section, the mid-turbine
frame including at least one support structure extending through an
interface between the first turbine case and the second turbine
case.
2. The gas turbine engine as recited in claim 1, wherein the
mid-turbine frame includes an airfoil for directing flow between
the first turbine section and the second turbine section.
3. The gas turbine engine as recited in claim 1, wherein an outer
end of the support structure is attached at the interface between
the first case and the second case.
4. The gas turbine engine as recited in claim 1, including a boss
through which the support structure extends and a fastening member
for securing the support structure to the boss.
5. The gas turbine engine as recited in claim 1, including a first
flange of the first case attached to a second flange of the second
case, with both the first flange and the second flange extending
transverse to the axis.
6. The gas turbine engine as recited in claim 4, wherein the at
least one support structure supports rotation of at least one
rotatable shaft extending through the turbine section.
7. The gas turbine engine as recited in claim 1, wherein the first
case and the second case each comprise continuous uninterrupted
structures.
8. A turbine section of a gas turbine engine comprising: a first
turbine supported for rotation about an axis; a second turbine
spaced axially aft of the for first turbine section for rotation
about the axis; a mid-turbine frame disposed between the first
turbine and the second turbine defining a passage between the first
turbine and the second turbine; a first case surrounding the first
turbine; and a second case surrounding the second turbine and
attached to the first case, wherein the mid-turbine frame extends
through an interface between the first case and the second
case.
9. The turbine section as recited in claim 8, wherein the
mid-turbine frame includes an airfoil for directing flow between
the first turbine section and the second turbine section.
10. The turbine section as recited in claim 9, wherein the
mid-turbine frame includes a support structure and an outer end of
the support structure is attached at the interface between the
first case and the second case.
11. The turbine section as recited in claim 10, including a boss
through which the support structure extends and a fastening member
for securing the support structure to the boss.
12. The turbine section as recited in claim 10, wherein the support
structure supports rotation of at least one rotatable shaft
extending through the turbine section.
13. The turbine section as recited in claim 8, including a first
flange of the first case attached to a second flange of the second
case, with both the first flange and the second flange extending
transverse to the axis.
14. The turbine section as recited in claim 8, wherein the first
case and the second case each comprise continuous uninterrupted
structures.
Description
BACKGROUND
[0001] A gas turbine engine typically includes a fan section, a
compressor section, a combustor section and a turbine section. Air
entering the compressor section is compressed and delivered into
the combustion section where it is mixed with fuel and ignited to
generate a high-speed exhaust gas flow. The high-speed exhaust gas
flow expands through the turbine section to drive the compressor
and the fan section.
[0002] Case structures support sections of the engine and are
joined at flanged connections. The turbine section will typically
include a high pressure turbine and a low pressure turbine that
each are disposed within separate case sections attached to each
other. In some engine configurations a mid-turbine frame is
disposed between the high pressure turbine and the low pressure
turbine and is supported by a separate case structure disposed
between cases for the high pressure turbine and low pressure
turbine sections. The mid-turbine frame provides support for
rotating engine components and includes support structures that
extend radially outward to the mid-turbine case structure.
[0003] Additional structures add cost, weight and complexity and
therefore it is desirable to develop more efficient case
structures.
SUMMARY
[0004] A gas turbine engine according to an exemplary embodiment of
this disclosure, among other possible things includes a fan
including a plurality of fan blades rotatable about an axis, a
compressor section, a combustor in fluid communication with the
compressor section, and a turbine section in fluid communication
with the combustor. The turbine section includes a first turbine
section disposed within a first case and a second turbine section
disposed within a second case. A mid-turbine frame is disposed
between the first turbine section and the second turbine section.
The mid-turbine frame includes at least one support structure
extending through an interface between the first turbine case and
the second turbine case.
[0005] In a further embodiment of the foregoing gas turbine engine,
the mid-turbine frame includes an airfoil for directing flow
between the first turbine section and the second turbine
section.
[0006] In a further embodiment of any of the foregoing gas turbine
engines, an outer end of the support structure is attached at the
interface between the first case and the second case.
[0007] In a further embodiment of any of the foregoing gas turbine
engines, includes a boss through which the support structure
extends and a fastening member for securing the support structure
to the boss.
[0008] In a further embodiment of any of the foregoing gas turbine
engines, includes a first flange of the first case attached to a
second flange of the second case, with both the first flange and
the second flange extending transverse to the axis.
[0009] In a further embodiment of any of the foregoing gas turbine
engines, the at least one support structure supports rotation of at
least one rotatable shaft extending through the turbine
section.
[0010] In a further embodiment of any of the foregoing gas turbine
engines, the first case and the second case each include continuous
uninterrupted structures.
[0011] A turbine section of a gas turbine engine according to an
exemplary embodiment of this disclosure, among other possible
things includes a first turbine supported for rotation about an
axis, a second turbine spaced axially aft of the for first turbine
section for rotation about the axis, a mid-turbine frame disposed
between the first turbine and the second turbine defining a passage
between the first turbine and the second turbine, a first case
surrounding the first turbine, and a second case surrounding the
second turbine and attached to the first case, wherein the
mid-turbine frame extends through an interface between the first
case and the second case.
[0012] In a further embodiment of the foregoing turbine section,
the mid-turbine frame includes an airfoil for directing flow
between the first turbine section and the second turbine
section.
[0013] In a further embodiment of any of the foregoing turbine
sections, the mid-turbine frame includes a support structure and an
outer end of the support structure is attached at the interface
between the first case and the second case.
[0014] In a further embodiment of any of the foregoing turbine
sections, includes a boss through which the support structure
extends and a fastening member for securing the support structure
to the boss.
[0015] In a further embodiment of any of the foregoing turbine
sections, the support structure supports rotation of at least one
rotatable shaft extending through the turbine section.
[0016] In a further embodiment of any of the foregoing turbine
sections, includes a first flange of the first case attached to a
second flange of the second case, with both the first flange and
the second flange extending transverse to the axis.
[0017] In a further embodiment of any of the foregoing turbine
sections, the first case and the second case each include
continuous uninterrupted structures.
[0018] Although the different examples have the specific components
shown in the illustrations, embodiments of this disclosure are not
limited to those particular combinations. It is possible to use
some of the components or features from one of the examples in
combination with features or components from another one of the
examples.
[0019] These and other features disclosed herein can be best
understood from the following specification and drawings, the
following of which is a brief description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 is a schematic view of an example gas turbine
engine.
[0021] FIG. 2 is a cross-sectional view of a turbine section of a
gas turbine engine.
[0022] FIG. 3 is a cross-section of an interface between a high
pressure turbine case and a low pressure turbine case.
[0023] FIG. 4 is a schematic view of an interface between the high
pressure turbine case and the low pressure turbine case.
DETAILED DESCRIPTION
[0024] FIG. 1 schematically illustrates an example gas turbine
engine 20 that includes a fan section 22, a compressor section 24,
a combustor section 26 and a turbine section 28. Alternative
engines might include an augmenter section (not shown) among other
systems or features. The fan section 22 drives air along a bypass
flow path B while the compressor section 24 draws air in along a
core flow path C where air is compressed and communicated to a
combustor section 26. In the combustor section 26, air is mixed
with fuel and ignited to generate a high pressure exhaust gas
stream that expands through the turbine section 28 where energy is
extracted and utilized to drive the fan section 22 and the
compressor section 24.
[0025] Although the disclosed non-limiting embodiment depicts a
turbofan gas turbine engine, it should be understood that the
concepts described herein are not limited to use with turbofans as
the teachings may be applied to other types of turbine engines; for
example a turbine engine including a three-spool architecture in
which three spools concentrically rotate about a common axis and
where a low spool enables a low pressure turbine to drive a fan via
a gearbox, an intermediate spool that enables an intermediate
pressure turbine to drive a first compressor of the compressor
section, and a high spool that enables a high pressure turbine to
drive a high pressure compressor of the compressor section.
[0026] The example engine 20 generally includes a low speed spool
30 and a high speed spool 32 mounted for rotation about an engine
central longitudinal axis A relative to an engine static structure
36 via several bearing systems 38. It should be understood that
various bearing systems 38 at various locations may alternatively
or additionally be provided.
[0027] The low speed spool 30 generally includes an inner shaft 40
that connects a fan 42 and a low pressure (or first) compressor
section 44 to a low pressure (or first) turbine 46. The inner shaft
40 drives the fan 42 through a speed change device, such as a
geared architecture 48, to drive the fan 42 at a lower speed than
the low speed spool 30. The high-speed spool 32 includes an outer
shaft 50 that interconnects a high pressure (or second) compressor
section 52 and a high pressure (or second) turbine section 54. The
inner shaft 40 and the outer shaft 50 are concentric and rotate via
the bearing systems 38 about the engine central longitudinal axis
A.
[0028] A combustor 56 is arranged between the high pressure
compressor 52 and the high pressure turbine 54. In one example, the
high pressure turbine 54 includes at least two stages to provide a
double stage high pressure turbine 54. In another example, the high
pressure turbine 54 includes only a single stage. As used herein, a
"high pressure" compressor or turbine experiences a higher pressure
than a corresponding "low pressure" compressor or turbine.
[0029] The example low pressure turbine 46 has a pressure ratio
that is greater than about 5. The pressure ratio of the example low
pressure turbine 46 is measured prior to an inlet of the low
pressure turbine 46 as related to the pressure measured at the
outlet of the low pressure turbine 46 prior to an exhaust
nozzle.
[0030] A mid-turbine frame 58 of the engine static structure 36 is
arranged generally between the high pressure turbine 54 and the low
pressure turbine 46. The mid-turbine frame 58 further supports
bearing systems 38 in the turbine section 28 as well as setting
airflow entering the low pressure turbine 46. The mid-turbine frame
58 is also sometimes referred to as sometimes as a turbine
intermediate case.
[0031] The core airflow C is compressed by the low pressure
compressor 44 then by the high pressure compressor 52 mixed with
fuel and ignited in the combustor 56 to produce high speed exhaust
gases that are then expanded through the high pressure turbine 54
and low pressure turbine 46. The mid-turbine frame 58 includes
vanes 60, which are in the core airflow path and function as an
inlet guide vane for the low pressure turbine 46. Utilizing the
vane 60 of the mid-turbine frame 58 as the inlet guide vane for low
pressure turbine 46 decreases the length of the low pressure
turbine 46 without increasing the axial length of the mid-turbine
frame 58. Reducing or eliminating the number of vanes in the low
pressure turbine 46 shortens the axial length of the turbine
section 28. Thus, the compactness of the gas turbine engine 20 is
increased and a higher power density may be achieved.
[0032] The disclosed gas turbine engine 20 in one example is a
high-bypass geared aircraft engine. In a further example, the gas
turbine engine 20 includes a bypass ratio greater than about six
(6), with an example embodiment being greater than about ten (10).
The example geared architecture 48 is an epicyclical gear train,
such as a planetary gear system, star gear system or other known
gear system, with a gear reduction ratio of greater than about
2.3.
[0033] In one disclosed embodiment, the gas turbine engine 20
includes a bypass ratio greater than about ten (10:1) and the fan
diameter is significantly larger than an outer diameter of the low
pressure compressor 44. It should be understood, however, that the
above parameters are only exemplary of one embodiment of a gas
turbine engine including a geared architecture and that the present
disclosure is applicable to other gas turbine engines.
[0034] A significant amount of thrust is provided by the bypass
flow B due to the high bypass ratio. The fan section 22 of the
engine 20 is designed for a particular flight condition--typically
cruise at about 0.8 Mach and about 35,000 feet. The flight
condition of 0.8 Mach and 35,000 ft., with the engine at its best
fuel consumption--also known as "bucket cruise Thrust Specific Fuel
Consumption (`TSFC`)"--is the industry standard parameter of
pound-mass (lbm) of fuel per hour being burned divided by
pound-force (lbf) of thrust the engine produces at that minimum
point.
[0035] "Low fan pressure ratio" is the pressure ratio across the
fan blade alone, without a Fan Exit Guide Vane ("FEGV") system. The
low fan pressure ratio as disclosed herein according to one
non-limiting embodiment is less than about 1.50. In another
non-limiting embodiment the low fan pressure ratio is less than
about 1.45.
[0036] "Low corrected fan tip speed" is the actual fan tip speed in
ft/sec divided by an industry standard temperature correction of
[(Tram .degree.R)/518.7).sup.0.5]. The "Low corrected fan tip
speed", as disclosed herein according to one non-limiting
embodiment, is less than about 1150 ft/second.
[0037] The example gas turbine engine includes the fan 42 that
comprises in one non-limiting embodiment less than about 26 fan
blades. In another non-limiting embodiment, the fan section 22
includes less than about 20 fan blades. Moreover, in one disclosed
embodiment the low pressure turbine 46 includes no more than about
6 turbine rotors schematically indicated at 34. In another
non-limiting example embodiment the low pressure turbine 46
includes about 3 turbine rotors. A ratio between the number of fan
blades 42 and the number of low pressure turbine rotors is between
about 3.3 and about 8.6. The example low pressure turbine 46
provides the driving power to rotate the fan section 22 and
therefore the relationship between the number of turbine rotors 34
in the low pressure turbine 46 and the number of blades 42 in the
fan section 22 disclose an example gas turbine engine 20 with
increased power transfer efficiency.
[0038] Referring to FIG. 2 with continued reference to FIG. 1, the
example turbine section 28 includes the high pressure turbine 54
disposed within a high pressure turbine case 62 and a low pressure
turbine 46 disposed within the low pressure turbine case 64.
Between the high pressure turbine 54 and the low pressure turbine
46 is the mid-turbine frame 58. The example mid-turbine frame 58
includes a vane 60 that directs flow from the high pressure turbine
54 into the low pressure turbine 46.
[0039] The mid-turbine frame 58 includes an I-rod 66 that extends
radially inward from the case 64 to support the bearing assembly
38. A support structure 88 extends between the I-rod 66 and the
bearing assembly 38. An I-rod boss 68 is supported on the case 64.
The I-rod 66 extends through the I-rod boss 68 and the low pressure
turbine case 64 and is secured at an outer end 82 by a fastener
that in this example is a threaded nut 70.
[0040] The example mid-turbine frame 58 extends across an interface
72 between the low pressure turbine case 64 and the high pressure
turbine case 62 such that additional case structures between high
and low pressure turbine cases 62, 64 are not required. The high
pressure turbine case 64 includes a first flange 74 that is
attached to a second flange 76 of the low pressure turbine case 64.
A fastening member 78 is utilized to attach the high pressure
turbine case 64 to the low pressure turbine case 64.
[0041] Referring to FIG. 3 with continued reference to FIG. 2, the
example low pressure turbine case 64 is axially rearward and
radially outward of the high pressure turbine case 62. As
appreciated other relative orientations between the low pressure
turbine case 64 and the high pressure turbine case 62 are within
the contemplation of this disclosure. The interface between the
high pressure turbine case 54 and the low pressure turbine case 64
includes the I-rod boss 68. The I-rod 66 extends through the low
pressure turbine case 64 and is fastened at an outer surface 90 of
the case 64 by the threaded nut 70. The nut 70 is torqued to hold
the I-rod 66 in place. The example I-rod 66 comprises a support
structure that supports a plurality of bearing structures 38 that
support rotation of the inner and outer shafts 440, 50. A gusset 57
can be utilized to provide additional stiffness and load
transfer.
[0042] The high pressure turbine case 62 includes a first stiffener
84 disposed axially forward of the interface 72. The stiffening
structure 84 maintains a desired stiffness and roundness of the
cases 62, 64 during operation and torqueing of the nut 70.
[0043] Referring to FIG. 4 with continued reference to FIG. 2, an
outer surface of the interface 72 between the low pressure turbine
case 64 and the high pressure turbine case 62 is shown. In this
example, a plurality of I-rods 66 are shown extending from the
interface of the turbine cases 62 and 64. The I-rod bosses 68 are
integral portions of each of the turbine cases 62 and 64 and mate
at the interface 72. The I-rod bosses 68 are not required to be of
an increased cross-sectional thickness because the interface 72
between the turbine cases 62 and 64 provides the desired rigidity
and structural stiffness for the I-rod 66. The interface 72 also
includes the first flange 74 and the second flange 76 that are
attached by way of the attachment members 78 and 80. In this
example, the attachment members 78 and 80 comprise a nut and bolt
configuration that extends through openings in corresponding first
and second flanges 74, 76.
[0044] Mounting of the mid-turbine frame 58 within one of the
example high pressure turbine case 62 and low pressure turbine case
64 eliminates a case structure and the fastening members and flange
configurations required to for attaching to the other case
structures. Moreover, the example interface 72 between the low
pressure turbine case 64 and the high pressure turbine case 62
integrates the I-rod boss 68 with the first and second flanges 74,
76 to provide a single connection interface between the low
pressure turbine case 64, the high pressure turbine case 62, and
the I-rod 66. The integration of all of these features into a
single attachment structure reduces cost, assembly, time and
weight. Moreover, the combined flanges of the example interface 72
provide improved stiffness control and improved resistance to out
of round conditions.
[0045] Although an example embodiment has been disclosed, a worker
of ordinary skill in this art would recognize that certain
modifications would come within the scope of this disclosure. For
that reason, the following claims should be studied to determine
the scope and content of this disclosure.
* * * * *